The present invention relates to a transmission and a shift mechanism for operating a transmission such as the inventive transmission. The invention will be described in connection with its use on a multi-speed bicycle, but its utility is not so limited.
It is known and common for transmissions for multi-speed bicycles to make use of a rear and main sprocket derailleur, the transmission when shifted disengaging a chain from one sprocket and engaging it with another. This requires a mechanism that will lift a chain and drop it into engagement with a larger or smaller sprocket, designedly but not necessarily the next larger or smaller sprocket. Operation of the prior art transmission is by an exposed or outside flexible cable which easily and constantly gets out of adjustment.
It is therefore an important object of the present invention to provide a transmission which completely eliminates the use of outside cables.
Another important object of the invention is to provide such a transmission which includes a housing in which all moving parts are totally enclosed.
A still further object of the invention is to provide such a transmission in which nothing can go out of adjustment.
An additional object of the invention is to provide such a transmission which eliminates the need for caliper brakes and enables a reversion to the old tried and true coaster brake hub on the rear bicycle wheel.
Yet another object of the invention is to provide an improved shift mechanism for use in operating the inventive transmission.
A still further object to the invention is to provide a shift mechanism which is such that in the shifting process, no gear can be skipped. For example, one can not go from first gear to third gear without stopping in second gear. This is a safety feature which prevents damage to the gears through jamming.
Further objects are to provide a transmission device and a shift mechanism which are relatively simple and economical in construction.
Additional objects and advantages will appear hereinafter.